1. Technical Field
The present disclosure relates to an optical element and a display device.
2. Related Art
Recently, an image display device of a type used by being worn on the head of an observer such as a head-mounted display is provided as one of wearable information devices. In addition, there is also known an image display device capable of simultaneously viewing both an image generated by a display element and an external image of the observer when the observer wears the image display device, that is, a so-called see-through type image display device.
For example, JP-T-2007-505353 discloses an optical device including a substrate with light transmittance, a display light source, optical means for combining light which is incident on the substrate by internal reflection and is in a field of view, and a partial reflection surface which is provided within the substrate and is disposed obliquely with respect to a main surface of the substrate. In addition, JP-A-2004-157520 discloses a see-through type display device system including an image generating device and a light guiding member including an image pickup system configured with a diffraction grating.
In the head-mounted display including the optical device disclosed in JP-T-2007-505353 and the display device system disclosed in JP-A-2004-157520, there is a problem hat striped display unevenness is viewed due to a pattern of the partial reflection surface provided in front of the eye of the observer. In addition, in the patent documents, it is described that uniformity of brightness can be improved and display unevenness can be eliminated by providing a region having different reflectivity in one partial reflection surface, but effects thereof are insufficient.